biological classification taxonomy biological taxonomy https://en.wikipedia.org/wiki/Category:Taxonomy_(biology) https://en.wikipedia.org/wiki/Taxonomy_(biology) The science of naming, defining (circumscribing) and classifying groups of biological organisms on the basis of shared characteristics. Organisms are grouped together into taxa (singular: taxon) and these groups are given a taxonomic rank; groups of a given rank can be aggregated to form a super-group of higher rank, thus creating a taxonomic hierarchy.